The purpose of this protocol is to compare the effect of intensive glycemic control alone to intensive glycemic control combined with reduction of insulin resistance with troglitazone treatment on reversing endothelial dysfunction in patients with type 2 DM. Specifically, based on recent suggesting that insulin resistance is independently associated with defects in endothelial function, we hypothesize that reversal of insulin resistance with troglitazone, in addition to glycemic control, will have a greater effect to ameliorate endothelial function than glycemic control alone. Such findings would greatly enhance the rationale for reversing insulin resistance independent of glycemic control in the treatment of patients with type 2 DM with the objective to reduce risk of macrovascular disease.